Azure Application Insights cost: you pay per GB of telemetry

Quick answer

Application Insights charges by data ingested, around $2.30 per GB after a small monthly free allowance, plus retention beyond the free 90 days. Cost tracks telemetry volume, so adaptive sampling, dropping noisy or verbose logs, and setting a daily cap are the levers that keep it down.

Application Insights, part of Azure Monitor, collects telemetry from your apps: requests, dependencies, exceptions, traces, and custom events. You pay for the volume of that telemetry, so the bill is a direct function of how much your apps emit.

Ingestion is the bill

After a small free allowance per month, ingested data costs around $2.30 per gigabyte. A chatty application emitting verbose traces and high-cardinality custom events can ingest surprising volumes, and the cost scales linearly with it. Retention beyond the default 90 days adds a per-GB-month charge.

Sampling is the main lever

Adaptive sampling keeps a representative fraction of telemetry while cutting volume, often dramatically, with little loss of insight. Enabling it is the single most effective control. Fixed-rate sampling gives you a predictable percentage when you want tighter control over volume.

Trim what you collect

Lever	Effect
Adaptive sampling	Keeps a representative subset, cuts volume
Drop verbose traces	Removes low-value, high-volume logs
Daily cap	Hard limit on ingestion per day
Shorter retention	Avoids per-GB-month retention charges

The same discipline applies as with Log Analytics and CloudWatch Logs: ingest the telemetry that earns its keep, sample the rest, and cap the total so a logging bug cannot run up the bill.

FAQ

How is Application Insights priced?

By data ingested, around $2.30 per GB after a small monthly free allowance, plus retention beyond the free 90 days. Cost scales directly with how much telemetry your applications emit.

How do I reduce Application Insights cost?

Enable adaptive sampling to keep a representative subset of telemetry while cutting volume, drop verbose or low-value traces, set a daily ingestion cap, and shorten retention beyond 90 days. Sampling is the highest-impact control.

What is adaptive sampling in Application Insights?

A feature that automatically keeps a representative fraction of telemetry and discards the rest when volume is high, preserving insight while sharply reducing ingested data and cost. It is the most effective lever for a chatty application.

Does retention affect Application Insights cost?

The first 90 days of retention are free; beyond that you pay a per-GB-month charge. If you do not need long retention, keeping it at or near 90 days avoids that additional cost.

Why did my Application Insights bill spike?

Usually a jump in ingested telemetry: a new verbose logging path, a burst of exceptions, or high-cardinality custom events. Check the ingestion breakdown, enable or tighten sampling, and set a daily cap to prevent recurrence.

Does C3X estimate Application Insights cost?

Application Insights cost is driven by ingested telemetry volume, a usage input. C3X prices the surrounding Azure infrastructure, and you model ingestion volume to estimate the per-GB charge.

What to do next

Estimate the infrastructure around your monitored app before you deploy. C3X reads your Terraform and prices your resources against a live catalog. Start with the quickstart.